Excel Inventory ADD Subtract can't figure out how :confused:

/ Totally Forgot to Introduce My Self Sorry Will post that somewhere else \

I have trouble to find a sollution for this problem.

I can write a whole story here what the problem is but i will add my sample workbook.

The problem in short:

I use a VLOOKUP to get the Part Number / Stock ect

And the i want to Add Value or Subtract Value and keep a History for each Part.

Hope this somewhat explains my problem.